Eidetic reduction

Ross Woods, 2020

Eidetic reduction is a technique in phenomenological studies, and usually deals with mental objects. (The term eidetic derives from Greek εἶδος “form.”)

The researcher has two complementary purposes:
• Identify the absolutely necessary and invariable components that make the object what it is.
• Remove what is perceived, and leave only what is required.

As a method, eidetic reduction is done by changing different elements of an object while observing whether or not it changes, in order to learn which characteristics are necessary for the object to remain itself without becoming something else. If a characteristic is changed and the object remains unchanged, the characteristic is unnecessary to the essence of the object, and vice versa. (If the object is changed, the characteristic is necessary to the essence of the object.)

It seems to have value beyond phenomenology in that it applies to the general nature of definitions, that is, what is essential to the definition and what is not. It is especially relevant when evaluating whether something is one entity or a combination of multiple entities.

See https://en.wikipedia.org/wiki/Eidetic_reduction
See also https://www.phenomenologyonline.com/inquiry/methodology/reductio/eidetic-reduction/